The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two families, the Leporidae (hares and rabbits), and the Ochotonidae (pikas). The name of the order is derived from the Greek lagos (λαγος) hare and morphē (μορφή) form.
Though these mammals can resemble rodents (order Rodentia), and were classified as a superfamily in that order until the early twentieth century, they have since been considered a separate order. For a time it was common to consider the lagomorphs only distant relatives of the rodents, to whom they merely bore a superficial resemblance.
However, they resemble rodents in that their teeth grow throughout their life, thus necessitating constant chewing to keep them from growing too long.